Structural and functional neuroimaging in amyotrophic lateral sclerosis

Abstract. Amyotrophic lateral sclerosis (ALS) is a fatal progressive central nervous system disorder affecting the upper and lower motor neurons. It is important to study the features of the course and progression of neurodegeneration in ALS, since no effective methods for treating this disease have been developed yet. Despite the clear evidence that brain lesions in ALS are of multisystem nature, there are no objective biomarkers of lesions of the upper motor neuron and the extramotor areas of the brain. Structural and functional neuroimaging, such as MR brain morphometry, diffusion tensor imaging, MR spectroscopy, functional MRI, positron emission tomography (PET), etc., have recently been playing a significant role in studying ALS. The results of neuroimaging studies are analyzed in this review in the context of using them to diagnose, predict, and monitor the course of ALS. Diffusion tensor imaging, MR spectroscopy, PET, combination of several neuroimaging methods and their combination with transcranial magnetic stimulation are the most sensitive and specific techniques to be used to diagnose the disease. Diffusion tensor imaging and MR spectroscopy can be used to monitor and predict the disease course. The main limitations and shortcomings of the performed studies, as well as the possible outlook for using neuroimaging in ALS, are discussed.